The field of this invention is shovels and in particular a new and improved shovel for maximizing lifting efficiency.
Perhaps the most common type of shovel or spade includes a single handle connected to a shovel blade. In this type of shovel, the user places one hand, the lifting hand, at some point on the main handle near to the shovel blade. The other hand, the control hand, is placed above the lifting hand nearer to or at the upper handle end. During lifting, the lifting load on the shovel blade acts as a downward force which must be overcome by an upward force exerted by the lifting hand. But the lifting hand must also overcome a downward force exerted by the control hand. For the control hand exerts a downward force to at least partly offset the moment force exerted by the load upon the lifting hand. Therefore, the lifting hand must exert an upward force to overcome not only the downward force of the load but also the downward force exerted by the control hand. This problem has been at least partly recognized in U.S. Pat. No. 3,436,111.
Attempts to improve upon the common shovel such as just described have been numerous, beginning more than a century ago as evidenced by patents. U.S. Pat. No. 61,784 discloses a snow shovel having an auxiliary handle connected to the rear of the shovel blade. U.S. Pat. Nos. 3,367,704; 2,416,414; 2,337,643; 1,411,166; and, 1,305,079 all disclose shovels which utilize an additional lifting handle which is connected to the shovel blade at the rear or upper end of the shovel blade, which is at the point of attachment of the shovel blade to the handle. U.S. Pat. No. 3,436,111 discloses a shovel blade which utilizes a main, offset handle for moving the position of the lifting hand nearer to the center of gravity of the load.
Other patents directed to the utilization of auxiliary lifting handles include U.S. Pat. Nos. 3,751,094; 3,466,078; 2,826,835; 2,772,910; 2,531,227; and, 826,928. All of these patents disclose the concept of auxiliary handles connected directly to the main handle, itself.